1. Systems and Models What are systems?
Can be living or non living
A cell, a car, a home, a farm
Can be open, closed, or isolated
Most in nature are open
Definition: A set of inter-related parts working together to make a complex whole

2. Types of Systems Open Closed Isolated
Exchanges matter and energy with its surroundings
All ecosystems are open systems
Closed
Exchanges energy but not matter
Earth is almost a closed system
Isolated
Exchanges nothing with environment
Do not exist naturally
Unless you count to whole universe

3. Systems Terminology Flows: When energy or matter move between storages
Transfers
When energy or matter flows and changes its location but does not change its state
Ex:
The movement of material in a non-living process (precipitation and water-flow from surface water to groundwater storage in the water cycle)
The movement of energy (radiating from a warm body into a cooler atmosphere)
The movement of material through living organisms (biomass being passed on as consumers eat organisms further down the food chain)
Transformations
A change in the chemical nature, state, or type of energy
Matter transformation: Amino acids converted to protein
Energy transformation: Ultraviolet light reflected from the Earth's surface as infrared light
Energy-to-matter transformation: Photosynthesis converting sunlight energy with CO2 and water into glucose
Transformation of state: Evaporation of water (transforms from liquid to gas)
Storages: When energy or matter remains stationary for a period
Systems Terminology

5. Models of Systems Can be physical or software Strengths Disadvantages
Easier to work with than reality
Can be used to predict the effect of change of input
Can be applied to similar situations
Help identify patterns
Can be used to visualize small and large things
Disadvantages
Accuracy lost to simplicity
If assumptions are wrong model collapses
Predictions can be inaccurate